Damper construction



Ap 1945- s. H. CHAPMAN 'ETAL 2,373,166

DAMPER coNsTRUcTIofi Filed Oct. 14, 1943 f Ni 3 m M u N PH R ww ,m

3% HF TR mW uT TR 5 Patented Apr. 10, 1,945

UNITED STATES, PATENT oFF cE DAMPER CONSTRUCTION Stuart H. Chapman, Lima, and Arthur F. Schultz,

, Springfield, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.., a corporation of Pennsylvania Application October 14, 1943, Serial No. 506,182

1 Claim. (Cl. 230-114) This invention relates to a damperconstruction, and more particularly to a damper construction which is especially suitable for regulating the amount of air delivered by a blower.

One object of this invention is to produce an improved damper construction.

A further object of this invention is'to produce a simple and inexpensive damper by means of which the air delivered by the blower may be varied from its full rated capacity to substantially zero, independently of and without changing the speed of the blower.

A still further object of this invention is to provide a damper of the type set forth which occupies minimum space and which can be readily attached to blowers already installed and in use, as well as to blowers of future manufacture, without material alteration of the structure of said blowers.

A still further object of this invention is to produce an adjustable control by means of which the accompanying drawing, forming a part of this application, in which:

. Fig. 1 is a view partly in vertical section and partly in elevation, showing a blower provided with a damper embodying the invention, with the damper shown in substantially closed position;

Fig. 2 is a section on line 11-11 of Fig. 1, cer tain parts being omitted; and

Fig. 3 is a fragmentary .view similar to Fig. 1, showing the damper in fully-open position.

Referring to the drawing more in detail, there is shown a centrifugal blower including a housing Ill having an air inlet l2 and an air outlet l4. In the housing In is disposed a blower wheel l6 which is keyedat 18 to a driving shaft 20. The shaft" is rotated by a suitable source of power such as an electric motor, not shown, and is journaled in bearings 22 in the hubs 24 and 26 which form part of, or are carried by, the blower housing ID.

The air inlet I2 is defined by an annular member 28 having an inner cylindrical surface 30 and an outer flaring or frusto-conical surface 32.

In order to effect uniform distribution, and to prevent eddying and turbulence of the air drawn into the housing ID by the blower wheel l6, stationary guide vanes 34 are mounted in concentric relation to each other and to the cylindrical surface 30 of the air inlet 12. The guide vanes 34 carry, or are provided with, outer, flaring or frusto-conical, portions 36, which are concentric with the frusto-conical surface 32 of the air in- .let l2. 'Any suitable retaining and spacing means, such as a spider or the like 33, may be used to secure the guide vanes 34 in position. As will be seen from Figs. 1 and 3 the spaces between the guide vanes 34 and their frusto-conical extensions 36 constitute air passages 31 through" which (air is admitted to the blower wheel 16.

In order to vary the amount of air admitted to the blower wheel It through the passages 31, a damper 39 is used which is adapted to coact with the vanes in the air inlet l2. Provision is also made for controlled manual or automatic movement of the damper relative to said inlet through a wide range of operation.

The damper. 39 includes a spider 40 and a number of concentric cylindrical members 42 adapted to coact with the frusto-conical portions 36 of the vanes 33 in the air inlet l2. As will be seen from Figs. 1 and 3, the cylindrical members t2 have an axial pathof movement at an angle to the frusto-conical portions 36 of the vanes 3E. The spider 40 is provided with a hub 44 which is slidably mounted on a fixed stub shaft or rod 636. One end of the stub shaft 46 is suitablysupported in position by the hub 26, and the other end thereof may be supported by any suitable means, such as a bracket or the like (not shown).

From Figs. 1 and 2 it will be seen that, as cylindrical members 42 are moved towards the air inlet l2, they enter into and gradually reduce or fully close the passages 31 between the frustoconical members 36, and vice versa. The cylindrical members 42 thus act as shutters for the openings 31. I

In order to move the damper 39 toward or away from the air inlet I2 and thus vary the capacity of the air passages 31, suitable actuating means, preferablyin the form of a bell crank 48, i employed. The bell crank 48 i fulcrumed at 50 to a fixed support 52 and has one arm 54 thereof secured at 55 to the hub 44 of the spider 4|]. The other arm 55 of the bell crank 48 is connected the I to an operating link or the like 58. The link 58 may be moved manually, or it may be moved automatically by a temperature, pressure, or loadresponsive member such as a thermostat, a diaphragm or the like. Since the particular device that may be used for moving the link 58 forms no part of the invention it is not shown nor described. v

In order to vary the ratio at which the damper 39 i moved in response to a, given movement of the link 58, the arm 55 of the bell crank 48 is provided with a series of openings or other calibrated engaging means 60, to which the link 55 may be selectively connected.

In order to be able to limit the extent to which the air inlet l2 may be opened, as when it is necessary to limit the capacity of the blower accordin to the operating capacity of the driving motor, an auxiliary adjusting device is employed. This adjusting device includes 'a lug or projection 66 which is carried by the bell crank 68, a fixed lug or the like 68, carried by the fixed support 52, and a set screw or the like movable in the lug 68. The lug 68 is so spaced from the lug 66 that, with the set screw completely retracted, the bell crank 48 is capable of the maximum range of movement for which it is designed.

Operation Assuming that it is desired considerably to reduce the amount of air drawn by the blower wheel E6, the link 58 is moved, manually or otherwise, in the direction of the arrow it, thus turning the bell crank it in counterclockwise direction and moving the spider 40 and the cylindrical members or shutters 42 towards the inlet open ng This position is illustrated in Fig. 1 from which it will be seen that the cylindr cal members 52 obstruct the major portions of the passages 37 between the frusto-conical portions 36, with the inner ends of the cylindrical members 62 disposed close to the corresponding surfaces of the frusto-conical portions 36. As shown in Fig. 1, the passages 31 are not entirely closed but it is to be understood that, if it is desired to close these passages completely, the spider i!) and the cylindrical members 32 will be moved until the inner edges of the cylindrical members 42 abut against the corresponding juxtaposed surfaces of the conical portions 36. If desired, the inner ends of the cylindrical members M or the juxtaposed surfaces of the portions 36, or both, can be provided with askets or the like.

If it is desired to admit maximum volume of air into the blower housing l9, the link 58 is moved in the opposite direction, thus turning the bell crank 48 in clockwise direction and moving the damper 39 away from the air inlet l2. Th s position is illustrated in Fig. 3 from which it will be.

to vary the ratio of movement of the damper 39- to the movement of the link 58. For example. where the actuating means, such as a diaphragm, thermostat or the like, provides a relatively hort movement of the link 58. the desired movement of the damper 89 may still be obtained by pivoting the link 68 to one of the openings 50 nearer to the fulcrum 50. Also, if it is desired to shorten the range of movement or the damper 39, the link 58 is pivoted to one of the openings 60 farther away from the pivot 50.

Where a blower embodying the construction described is applied to apparatus already installed, this ability to make adjustments without disturbing the already installed diaphragm, thermostat or actuating means is quite advantageous.

If it is desired to limit the maximum capacity of the blower, to correspond to the capacity of the driving motor, or because of other requirements, the set screw 10 is turned until its inner end projects beyond the inner face of the lu 68, thus constituting a stop in the path of the lug 66 and accordingly limiting the movement of the bell crank 48. The space between the lugs 8-6 and 68 is-such that, with the set screw completely retracted, the lug 66 will contact the lug 68 only when the damper 39 has been moved to its fully open position shown in Fig. 3. In this position the screw Iii does not in any way curtail the normal range of movement of the damper and the lug 68 serves as a stop to prevent damage in the event that undue force is exerted in opening the damper 39. Likewise, the hub 46 provides a stop against which the hub 44 abuts to limit the inward movement of the damper 39 and guard against damage in the event that undue force is exerted in closing the damper 39.

It will thus be seen that this invention provides a simple and inexpensive damper construction which is adapted for manual as well as automatic operation, which occupies minimum space and which is capable of infinite adjustment .within its range of operation. It will also be noted that the damper is readily adapted for cooperation with any given automatic actuating means by merely changing the connection of the link 58 to the arm 56 of the bell crank 48, or by adjusting the set ,screw ill, or both, without the necessity of adjusting or replacing any already installed automatic temperature, pressure or load-responsive device by which the link 58 is to be actuated.

While the damper is shown associated with a centrifugal blower, it is equally applicable to a propeller type blower.

As illustrated in the drawings, the cylindrical members 42', carried by the spider 40, are movable while the rrusto-conical members 36 are stationary. However, it is within the scope of this invention to reverse this order by making the cylindrical members 42 stationary and the rrustoconical portions 38 movable.

It is also pointed out that the guide vanes 34 may be omitted without departing from the scope of the invention. If the guide vanes 36 are omitted, the trustoconical portions 36 can be mounted directly in and at an angle to the cylindrical opening 36 of the air inlet, and the movement of the cylindrical members 42 relative to the inlet l2 will continue to open or close the passages 3'! between the frusto-conical portions 36 in the same manner as above described.

While as illustrated in the drawing, the inlet of the blower casing is shown round and the damper elements 42 are shown as concentric cylindrical members, it is within the scope of the invention to apply the principle of operation illustrated to air-inlets of a square, rectangular or other shape in which the damper elements would be in the nature of a grill which is movable into and out of oblique passages having corresponding configuration. g

Also, while in the embodiment illustrated, the damper is shown applied to the inlet side of a blower, it may be applied to the outlet or discharge side thereof without departing from thespirit or scope of the invention.

A special advantage of the construction ilor the invention to make the guide vanes of any. desired contour so as to direct the air to the blower wheel- IS in any desired fashion. v

Finally, it is pointed out that while the invention has been illustrated as applied to a blower duct or passage through which any fluid is flowing with or without forced draft. r a

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible placed thereupon as are specifically set forth. in the appended claim.

.What is claimed is:

A housing having inlet and outlet openings,.

9. fluid moving element for moving a fluid through said openings and said housing, at least one of said openings being defined by a wall structure including an inner cylindrical section and an outer frusto-conical section forming a continuation of said cylindrical section, a plurality of wheel, it may be equally well applied to any of various changes and modifications without de- J portions of said guides.

spaced concentric guide fixed in said openings, each of said guides includin an inner cylindrical portion registering with said cylindrical section and an outer frusto-conical portion registering with said frusto-conical section, whereby con centric fluid passages having oblique outer and straight inner portions are formed, andmeans for closing or opening said passages comprising a plurality of spaced cylindrical shutters of substantially the same diameter as, and concentric with, the cylindrical portions of said guides, and means for moving said shutters towards and away from the cylindrical portions of said guides in interleaving relation with the outer conical STUART HYKCHAPNILAN. ARTHUR F. scrmmz.

parting from the spirit thereof. and it is desired," therefore, that only such limitations shall be 

